Reliability of Measures of Job Demands and Job Decision Latitude

(“new” indicates articles published since the review article by Schnall et al., 1994 was published; reference numbers are from the review article)

In most studies where scale reliability is reported, coefficient alpha for job demands and job decision latitude is above .70. In the New York City ambulatory blood pressure study the following values were reported for men at Time 1 for job demands, job decision latitude, workplace social support, and their components:

Four studies from Sweden as well as one from Australia and one from the U.S. have also reported values for scale reliability using a variety of scale items. These studies are:

49.

Johnson, J. V., Hall, E. M. 1988. Job strain, work place social support, and cardiovascular disease: A cross-sectional study of a random sample of the Swedish working population.Am J Public Health 78:1336-42.

In the U.S., many studies have used the basic set of 14 items from the U.S. Quality of Employment Surveys to measure job demands (5 items) and job decision latitude (9 items). One of these studies, in addition to the New York City ambulatory blood pressure study, used subjects’ individual self-reports to measure job characteristics:

Since few studies have measured job characteristics at more than one point in time, our study at Cornell is one of the few studies (other than QES) which can provide test-retest reliability. In our sample , among men, over three years, test-retest reliability was r=0.64 for both job demands and job decision latitude — and that includes people who changed job titles (data in paper under review).

The job strain measure is derived from the Job Content Questionnaire. This is a 42-item questionnaire developed by Robert Karasek, MD, PhD, based, in part, on questions drawn from the US Department of Labor/University of Michigan Quality of Employment Surveys. Two scales are used to define job strain-decision latitude and psychological demands.

The first scale, decision latitude, is defined as the sum of two subscales given equal weight:

Skill discretion, measured by six items (keep learning new things, can develop skills, job requires skills, task variety, repetitious, and job requires creativity), and decisionauthority, measured by three items (have freedom to make decisions, choose how to perform work, and have a lot of say on the job).

The second scale is psychological job demands, defined by five items (excessive work, conflicting demands, insufficient time to work, work fast, and work hard). All questions are scored on a Likert scale of 1 to 4, and psychological demands ranges from 12 to 48 while decision latitude ranges from 24 to 96. (In published papers from the Cornell Blood Pressure Study, a slightly different formula was used to compute the decision latitude scale score, in which the score was not multiplied by 2. Therefore, in papers from the Cornell study, the decision latitude score ranges from 12 to 48.)

The Job Content Questionnaire is copyrighted. Further information regarding the Job Content Questionnaire (referred to as the JCQ) including permission for its use and instructions for scoring, please visit their website.

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